The Iranian population includes several ethnic groups scattered throughout Iran, which differ with regard totheir rates for cancer. An infamous ‘Asian esophageal cancer belt’ stretches to the east from the Caspian littoral inIran via Turkmenistan to the Northern provinces of China. Apart from the eastern part of the Caspian littoral areaof Iran which has the highest incidence of esophageal cancer in the world, other parts of the country have variablerates, ranging from 3 to more than 15 cases per 100,000 population, but rates have decreased sharply in the highincidence areas. Studies of the etiology of esophageal cancer in Iran and especially among the Turkmen ethnicpopulation have indicated that several factors are behind the striking high incidence. Certain risk factors such as afamily history of esophageal cancer, low socioeconomic status and poor nutritional diet are well studied and plausibleevidence for their etiologic contributions exist. While thermal irritation and coarse food (physical damage to themucosal lining of the esophagus) have attracted attention in correlational studies, conclusions about their etiologiccontribution are inconclusive.